MiR200c-3p Regulates Apoptosis And Proliferation Of Endothelial Cell And Phenotype Transformation Of Vascular Smooth Muscle Cells In Aortic Dissection

Objective: The purpose of this study was to explore the expression and distribution of miR200c-3p in aortic dissection(AD),and its effect on the function of vascular endothelial cells.This study explored the specific target m RNA and signal pathways regulated by miR200c-3p,and its role in the interaction between human umbilical vein endothelial cells(HUVEC)and human arterial smooth muscle cells(HASMC).Methods: The expression of miR200c-3p in human aorta and serum was detected by RT-qPCR.We used FISH/IF to explore the co-localization of miR200c-3p and endothelial cells in human aorta.The effect of miR200c-3p on the proliferation of HUVEC was detected by CCK-8method.33342 staining,TUNEL staining,flow cytometry and WB were performed to assess the HUVEC apoptosis.The possible targets of miR200c-3p were screened by bioinformatics methods,and the targeted regulation relationship between miR200c-3p and CASZ1 was clarified by dual-luciferase reporter gene assay.RNA interference was used to decrease the expression of CASZ1 and evaluate its effect on the function of HUVEC.CASZ1 affected Rho A/Egfl7 was detected by western Blotting(WB).After the expression of miR200c-3p in HUVEC was regulated in the co-culture model,the apoptosis of HASMC was detected by cell flow cytometry.The migration ability of HASMC was assessed by traswell experiment and scratch test,and the the marker proteins of phenotypic change were detected by WB.Further,the expression of major inflammatory factors and metalloproteinases in HUVEC were detected by RT-qPCR and ELISA.In the mice AD models,which were constructed using BAPN and Ang II,the incidence of dissection between each group was counted.To detect the morphological changes in the aorta and the relative content of elastic fiber in each group,HE and EVG staining were carried out.Results: MiR200c-3p was highly expressed in vessels and serum in AD patients,and mainly localized in vascular endothelial cells.MiR200c-3p could inhibit HUVEC proliferation and promote HUVEC apoptosis.Using bioinformatics methods and expression verification,we found CASZ1 may be a target directly regulated by miR200c-3p.Silencing CASZ1 also inhibited proliferation and promoted apoptosis of HUVEC.Rescue assay showed that CASZ1 low-expression could restore the effect of down-regulated miR-200c-3p on HUVEC cells.The above viewpoint was verified by dual-luciferase reporter gene assay.It was confirmed that down-regulated CASZ1 could significantly inhibit Rho A/Egfl7 pathway using WB assay.Besides,the co-culture of HUVEC and HASMC showed that the increased miR200c-3p could significantly promote the migration of vascular smooth muscle cells.The increase of IL-1β was detected in HUVEC supernatant of up-regulated miR200c-3p group.In vivo,it was observed that overexpression of miR200c-3p could significantly increase the incidence of dissection in mouse model,and reduce the diameter ratio of mesomembrane lumen and expression of elastic fiber.Conclusion: MiR200c-3p inhibits the proliferation of HUVEC and promotes its apoptosis through suppressing CASZ1 expression,leading to downregulation of the Rho A/Egfl7 pathway.Moreover,it promotes the phenotype switching of HASMC in vitro and participates in the vascular remodeling of dissection in vivo.Our study suggests that miR200c-3p may be a new diagnostic biomarker and therapeutic target for AD.